Electrical separator.



P. O. SCHNELLE.

ELECTRICAL SEPARATOR.

APPIIOATION FILED JUNE 15, 1904.

1,071,354,, Patented Aug.26,1913.

ennui) STATES PATENT OFFICE.

FRIEDRICH OSCAR SCI-INELLE, OF FRAFIKEEORT-ON-THE-MAIN, GERMANY.

ELECTRICAL. sisraaaroa.

Patented Aug. 26,1913.

Application filed June 15, 1904. SeriaI No. 212,665.

To call whom it may concern Be it known that I, FRIEDRICH OSCA SGHNELLE, electrical engineer, residing at 18 Guio-llettstrasse, Frankfort-on-the Main, Germany, have invented new and useful Improvements in Electrical Separators, of which the following is a specification.

This invention relates to the dry separation or concentration of comminuted,granu lar materials, ores, minerals and similar products whose ,1 individual: particles or grains differ in their susceptibility to electrostatic charges. the separation in a Its object is to carry out simple and effective way fit for industrial application on a large scale.

I am aware that it has been proposed to utilize both electrostatic attraction and repulsion for separating commingled materials and that various forms of apparatus have been designed for that purpose, but owing to the difficulty of obtaining a clean separation and to the small output and unreliable working of the machinery electric separation has found but a very limited commercial application. These difficulties are overcome by the present invention according to which the separation is effected under essentially different conditions as will be more fully explained hereinafter.

The physical foundation of my invention- I understand to be the generation of an intense electrostatic'field of force upon a comparatively narrow zone, preferably at. or near the borders or edges of a suitably shaped body, to which an electrostatic charge may be imparted, either by conduction br induction. I judge this fromthe fact thht particles of commingledmaterial spread over the upper surface of such a body appear to be unaffected by a charge of suitable potential "as long as they remain at certain distancesay about one -inch-frotn the active zone. .The kinetic action of the charge upon the particles being thus practically confined toa relatively narrow margin a distinct differentiation between the particles to be-separated is effected by movmg the mixture upon the said surface into in the direction of the electrostatic lines of' force emanating from its border; the particles less susceptible to-the influence of the bination The particles of higher instance field are but slightly affected by the charge and drop off the surface closer by the edge. I have found that the effect is the more marked the closer the said zone of action is confined to the border or edge of the surface uponwhich-the material is spread out.

The manner in which the commingled ma-- terials may befed upon the surface of the separating body, the means by which they may be conveyed or transported to the active zone, separated and collected separately will be readily understoodby reference to the annexed drawings, in which- Figure 1 is a vertical central section through a complete separating macnine. Fig. 2 is a diagrammatic sketch of a comof several apparatuses similar to Fig. 1, Fig. 3 is a front view of another type of separator, Fig. 4 is avertical section along the broken line XX of the apparatus shown in Fig. 3.

Like letters refer to similar parts throughout the several drawings.

Referringto Fig.1, A represents a coni al; feed hopper to whihh the separating b dy B, in the shape of a flat cone is rigidly attached. The hopper A is supported by 3 rollers L groovedor corrugated around their circumference as indicated in the drawing. The rollers L are carried by the ring R which is supported by 3 or more columns resting upon the wooden frameC. One of the rollers L is driven bya pulley P thereby causing cone B to rotate about'the common axis. Theicorrugationsof the rollers L superpose upon the slow rotation a quick vibratory or shaking motion, which will e referred to more particularlyhereinafter. Under and surrounding the cone' B is a system of conical receptacles D andv E provided with outthe hopper A togetherwith the.

lets emptying into the boxes I and II. The

truncated gonical surface Z indicated by dottedlihesas surrounding the separator cone B will be hereinafter referred to. The columns S are 'to be; of insulating material such" as hard rubber 'or glass all other parts may consist wholly or less otherwise stated).

partly of metal (un- The ring R is con nected to the one terminal of. a suitable source of high potential electricity as-for an electrostaticmachine. The charge is transmitted by means of therollers L to the hopper A and to the cone 13. The other pole of the generating apparatus may be groundedand correspondingly also the hopper A and the cone B causes the 1 materials. It is important, however, to note that while gravity coacts with the kinetic.

potential material contained in the hopper A to spread out over the surface of the cone B in an evenly distributed film. Upon approaching the rim of the-cone B the separation takes place, as indicated in the figure and in accordance with the general observations above described. The diflerent products are caught by the receptacles D and E and thence emptied into the boxes I and II respectively, the box I receiving the strongly excitable material, the box II the more indiiferent particles, 2'. 6. those which are less susceptible to electrification. The active zone of the separating body B may be still more intensified or condensed at the rim or edge by opposing to the same an annular or conical conductor such as indicated by Z, this conductor being of different potential to that of the cone B. The conductor Z may be charged with the opposite polarity to that of the cone B by connection with the other pole of the generator used for charging the cone B. In these cases however care must be taken that this conical ring does not disturb the path of the falling materials which would be the case if this body was laid too closely around or above the mm of the cone B for then the particles of higher susceptibility would be strongly attracted by the said opposite pole and after contacting with the same be rejected toward the inner collecting hopper D thereby. disturbing the separation and spoiling the products. This is avoided by calling the force of gravity into play in: directing the path of the falling action due to the electrostatic field in determining the curve followed by the stream of falling particles, deviating them from the direction of the electrostatic lines of force, the. separation itself is essentially determined by the specific action of the electrostatic charge. In case an insulated conductor as indicated by Z charge with a suitable is used as an op osing pole to the rim of thexcone B, the latter may also be charged by induction from Z and in this case the hop er A carryin the cone B would not need to. insulated om the earth.

In regard to the shape of the cone B it is to be noted, that its elements need not be straight lines but are by preference curves, flattening out toward the circumference. It

middlings is further to be noted that the rim must not be sharp-edged in order to produce the desired field concentration for giving the best results, but according to my experiences it is rather advantageous to give the same a more or less rounded-off profile.

While I have found the shape of the flat tened cone B as represented in the drawing (Fig. 1) in combination with its vibratory motion of special advantage for an even distribution of the material upon its surface, and for presenting the particles to be separated to the active zone or rim, I

wish it to be understood that the shape of this surface may be varied in many ways without departing from the spirit of thisinvention. Thus, for instance, the inclination of the conical surface may be such that the material will glide down by its own weight without any motion being imparted to the said surface.

Fig. 2 shows a combination of three separating cones B B B mounted upon a common shaft by whicha suitable motion as well as the electric charge may be transmitted to the cones. The cone B receives the commingled materialdireetly from the hopper A, after separating out the majority of particles of highest susceptibility, the indiiferent material together with and the remaining port-ion of highly susceptible material are subjected to a second separation by means of B and likewise to another repetition upon B the final products being collected from D and E as I and II similarly to Fig. 1.

It is evident that by such a repetition the capacity of the apparatus can be raised and the quality of the product improved. Figs. 3 and 4 show a linear type of separator likewise embodying my invention.

Instead of the conical hopper in the previous figures a long V-shaped trough like hopper A is used here to receive the material to be separated. A narrow opening or slot passes through the bottom of the hopper A from end to end of the same. Underneath this slot is a rectangular bar T supported by the two levers K; Some distance below T is small trough V and immediately under t e same fiat bar B slanting to both sides and rounded off at the edges. The trough V as well as the fiat bar B? arelikewise fastened, at each end to one of the levers K. The latter are here suppo ed to be of insulating material, and are piv tally supported by the pins Q, projecting from'the end walls of the hopper A.

In orderto impart to these levers an o'scil:

two eccentric pins Y set off a common shaft driven by the pulley P. The hopper A is supported by the wooden frame C whichalso carries the bearings for the driving ,zone of repulsion at said border shaft and the pulley P. Below the fiat'bar B are the receiving boxes I, II, I inclosed by adjustable partitions F and side walls H. The parts V and B are to be connected to the one pole of a generator of high tension electricity, while the receiving receptacles and all other parts of the apparatus may be grounded or connected with the other pole of the generator. The action of this machine is essentially analogous to that of the annular type previously described. It is evident that the oscillatory motion impart-ed to the bar T by the levers K causes the granular material contained in the hopper A to be fed in a thin film from either side into the trough V and thence on to the upper surface of B The vertical distance through which the material has to fall is determined in this case by the necessity of insulating the parts V and B from the downwardly projecting portions of the hopper A. In all other respects the separating process is analogous to that above described and will be readily understood from the drawing Fig. 3.

Modifications corresponding to those described in connection with Figs. 1 and 2 may also be executed in the linear form, and all that has been said in regard to the electrical and mechanical functions of the cone B (Fig. 1) similarly applies to the linear separating body B (Fig. 3).

Other modifications of the apparatus will readily suggest themselves, thus the laterally oscillating or swinging motion given to the parts K, V and B Fig. 3 may be replaced by a longitudinally reciprocating movement which would again suggest a common actuating mechanism for a number of superposed linear separating devices similar to Fig. 2. My invention, therefore, is not limited to the special forms illustrated by the annexed drawings.

Now what I claim and desire to secure by Letters Patent is the following:

1. An electrostatic separator, having an inclined conductor provided with a border edge or verge, means for charging said con ductor electrostatically, means for feeding a commingled mass of particles of different susceptibilities'to electrical repulsion to said conductor, means for causing said particles to pass on uninterruptedly over the upper surface of the conductor until they reach the said border edge or verge, whereby the mass as it passes over the edge or verge is subjected tothe separating action of the intense edge just as the mass is about to drop therefrom, and a dividing and guiding barrier interposed between the paths of outward trajectory of the separated particles of. different susceptibilities to electrical repulsion as they pass over said edge or verge, said barrier being likewise interposed in the path of possible subsequent commingling of the separated particles: substantially as described.

2. An electrostatic separator. having an inclined conductor provided with a border edge or vergehaving a surface rounded in cross-section, means for charging said conductor electrostatically, means for feeding a comminglcd mass of particles of different susceptibilities to electrical repulsion to said conductor, means for causing said particles to pass on uninterrllptcdly ovcr the upper surface of the conductor until they reach the said border edge or vcrge, whereby the mass as it passes over the edge or verge is subjected to the separating action of the intense zone of repulsion at said border edge just as the mass is about to drop therefrom, and a dividing and guiding barrier interposed bctwccn the paths of outward trajectory of the separated particles of different susceptibilities to electrical repulsion asthey pass over said edge or verge, said barrier being likewise interposed in the path of possible subsequent commingling of the separated particles; substantially as described.

3. An electrostatic separator, having an inclined conductor provided with a border edge or verge, means for imparting to said conductor an electrostatic charge of a given sign, means for feeding a comminglcd "mass of particles of different. susceptibilities to electrical repulsion to said conductor, means for subjecting the mass to the siuulltancous action of gravity and of said edge as the mass passes over the latter, an outlying conductor and means for imparting to it an electrostatic charge of opposite sign, said outlying conductor being within a sutlicient range to augment the intensity of the separating field at the said edge or verge of the inclined.conductor, and a separating and guiding barrier-intcrposed between the paths of trajectoryjof the separated particles of different susceptibilities to electrical repulsion asthey pass over said cdge or verge, said barrier being likewise interposed in the path of possible subsequent commingling of the separated particles; substantially as described.

4. An electrostatic separator. comprising a conical conductor, a hopper for supplying the particles to be separated to the apex of said conical conductor. means for rotating the conical conductor and its supply hopper, means for imparting an electrostatic charge to said conical conductor. and means for separately collecting the separated grades of material; substantially as described.

5. An electrostatic separator. comprising a conical conductor, a hopper for supplying the particles to be separated to the apex of said conical conduct-or. means for imparting an electrostatic charge of a given sign to said conical conductor, an outlying cylindrical conductor and means for imparting to it an electrostatic charge of opposite Sign, and means for separately collecting the separated grades of material; substantially as described.

6. Anclectrostatic separator, comprising a conical comluctor, a hopper for supplying the particles to be separated to the apex of said conical conductor, means for imparting an electrostatic charge to said conical conductor, and a. divider projecting into the;

trajectories of material repelled from the \'er; u ot' the base of the cone;

substantially as described.

7. An electrostatic separator, comprising a conical conductor, a hopper for supplying the particles to be separated to the apex of said conical conductor, means for imparting an electrostatic charge of a given sign to said conical conductor, an outlying cylindr' tal conductor and means for imparting to it an electrostatic charge of opposite sign and a divider projecting into the trajectories of material repelled from the verge at the base of the cone; substantially as described.

In testimony that I claim the foregoing as my invention, I have signed my name in presence of two Witnesses, this 31st day of May 1904:.

FRIEDRICH OSCAR SCHNELLE lVitnesses:

ROBERT Bt'JHL, JEAN GRUN D. 

